Integrated circuit (IC) chips are usually incorporated into a package. Such packaging provides, for example, physical and environmental protection as well as heat dissipation. Moreover, packaged chips typically provide electrical leads to allow integration with further components.
Several IC packaging techniques have been developed. One such technique, for example is described in, Lee et al., “Embedded Actives and Discrete Passives in a Cavity Within Build-up Layers,” U.S. patent application Ser. No. 11/494,259 filed on Jul. 27, 2006 and published as US 2007/0025092 A1 on Feb. 1, 2007, the content of which is hereby incorporated by reference in its entirety. Lee et al. discloses, inter alia, a so-called chip-last approach.
In contrast to a chip-first or chip-middle process, a chip-last approach embeds a given chip after all build-up layer processes are finished. The advantages of this approach are now well known, however, chip-last packaging is not thought to be appropriate for all chip types. For example, for ICs having a back side contact, and for those chips whose operating parameters call for dissipation of higher quantities of heat, such as power chips and high-performance logic chips.